Haiku is a kind of Japanese poetry. It was given this name in 
the late 19th century by Japanese writer Masaoka Shiki 
from a combination of the older hokku and the haikai 
(or verses) in haikai no renga. Haiku, when known as 
hokku were the opening verses of a linked verse form, 
haikai no renga. In Japanese, hokku and haiku are 
traditionally printed in one vertical line (though in 
handwritten form they may be in any reasonable number of lines). 
In English, haiku are written in three lines to equate to 
the three parts of a haiku in Japanese that traditionally 
consist of five, seven, and then five on (the Japanese 
count sounds, not syllables; for example, the word 
"haiku" itself counts as three sounds in Japanese 
(ha-i-ku), but two syllables in English (hai-ku), and 
writing seventeen syllables in English produces 
a poem that is actually quite a bit longer, 
with more content, than a haiku in Japanese).